RU2735193C2 - Method of controlling motor of vehicle and device for controlling engine and motor of vehicle - Google Patents

Abstract

FIELD: vehicles.

SUBSTANCE: in the vehicle motor control method, it is actuated to perform power rotation, so that vehicle deceleration becomes less or equal to prescribed value, when fuel injection for engine stops during deceleration and engine rpm is greater than or equal to preset rotation speed. Vehicle engine and motor control device comprises a fuel cut-off control unit, when engine rpm is greater than or equal to preset rotation speed during deceleration and deceleration control unit actuating motor to perform power rotation, so that vehicle deceleration becomes less or equal to prescribed value when fuel injection for engine is stopped.

EFFECT: improved fuel efficiency.

4 cl, 9 dwg

Description

The technical field to which the invention relates

[0001] The present invention relates to a vehicle control method and a vehicle control apparatus that contribute to improving fuel economy by stopping fuel injection for an engine while driving.

State of the art

[0002] Patent Document 1 discloses a technology in which when the vehicle deceleration is greater than a prescribed value, the control (hereinafter referred to as fuel cut control) to stop injection of fuel for the engine is stopped and the engine is restarted.

Prior art documents

Patent documents

[0003] Patent Document 1: Japanese Laid-open Patent Application No. 2015-134585

The essence of the invention

The problem solved by the invention

[0004] However, according to the technology of Patent Document 1, since the fuel cut control is stopped to suppress deceleration, it is thus difficult to sufficiently improve the fuel economy.

An object of the present invention is to provide a method for driving a vehicle that can improve fuel efficiency.

Problem Solver

[0005] In order to achieve the object described above, in the vehicle driving method according to the present invention, during the fuel cutoff control, the motor adapted to apply torque between the engine and the drive wheels is instructed to perform force rotation, so that deceleration vehicle does not exceed the prescribed value.

Results of the invention

[0006] Therefore, it is possible to continue the fuel cut control while suppressing deceleration and improve fuel economy.

Brief Description of Drawings

[0007] FIG. 1 is a diagram of a vehicle system to which the fuel cut control of the first embodiment is applied.

FIG. 2 is a control block diagram for performing fuel cut control of the first embodiment.

FIG. 3 is a flowchart showing a deceleration control process during fuel cutoff of the first embodiment.

FIG. 4 is a timing chart when the SSG generates a regenerative torque during deceleration during the fuel cut control of the first embodiment.

FIG. 5 is a timing chart when the SSG does not perform power rotation or recuperation during deceleration during the fuel cut control of the first embodiment.

FIG. 6 is a flowchart showing a deceleration control process during fuel cutoff of the second embodiment.

FIG. 7 is a timing chart when the SSG generates a regenerative torque during deceleration during the fuel cut control of the second embodiment.

FIG. 8 is a timing chart when the SSG does not perform power rotation or recuperation during deceleration during the fuel cut control of the second embodiment.

FIG. 9 is a timing chart showing the process of suppressing the engine speed fluctuation in the FC ending process of the second embodiment.

Reference character descriptions

[0008] 1 Engine

2 Clutch

3 Continuously variable transmission of belt type

4 Oil pump

10 Drive wheel

11 Motor / Generator (SSG)

12 Battery

13 Compressor

C1 Automatic transmission control unit (ATCU)

C2 Engine control unit (ECU)

C3 SSG Control Unit (SSGCU).

Embodiments for carrying out the invention

[0009] First embodiment

FIG. 1 is a diagram of a vehicle system to which the fuel cut control of the first embodiment is applied. In the vehicle, the rotation that is output from the engine 1, which is an internal combustion engine, is introduced into the belt-type continuously variable transmission 3 through the clutch 2. Clutch 2 is a blocking clutch provided for the torque converter. The rotation, the speed of which is switched by the continuously variable transmission 3 of the belt type, is transmitted to the pair of driving wheels 10 through the final gear, and the like. Engine 1 includes a starter generator 11 (hereinafter referred to as SSG 11), which functions as a starter motor as well as a generator, a battery 12 that sends and receives electrical power to and from SSG 11, and an air conditioning compressor 13 air. An oil pump 4 is provided on the output shaft of the engine 1, and the continuously variable transmission 3 of the belt type is controlled by the hydraulic pressure of the oil pump 4. An electric oil pump or the like. may be provided and no separate limitation is imposed.

[0010] FIG. 2 is a control block diagram for performing fuel cut control of the first embodiment. The vehicle contains an automatic transmission control unit C1 (hereinafter also referred to as ATCU), which controls the engagement state of the clutch 2 as well as the shift state of the belt-type CVT 3, engine control unit C2 (hereinafter also referred to as ECU), which controls the operating state of engine 1, and the SSG control unit C3 (hereinafter referred to as SSGCU), which controls the operating state of SSG 11.

[0011] The vehicle also includes a turbine sensor 21 that detects a turbine speed (hereinafter also referred to as Nt), which is equal to the engine side rotation speed for the clutch 2, a vehicle speed sensor 22 that detects the vehicle speed ( hereinafter also referred to as VSP), an accelerator opening degree sensor 23 that detects an accelerator opening degree (hereinafter also referred to as APO), a brake switch 24 that detects whether the brake pedal 5 has been depressed, an engine speed sensor 25, which detects the engine speed Ne, and a SOC sensor 26 that detects the state of charge SOC of the battery 12. In addition to the sensors described above, the vehicle further comprises a crank angle sensor that detects the engine crank angle, a cam angle sensor shaft, which ry detects the camshaft angle, a hydraulic pressure sensor that detects various control oil pressures supplied to the CVT 3-belt type, a current sensor that detects the SSG 11 current value, a voltage sensor that detects the SSG 11 voltage value, etc. ...

[0012] Detection signals of various sensors are supplied to each control unit. The control units are connected by a CAN communication line, so that they can transmit and receive control information mutually. Therefore, from various sensors, for example, the accelerator opening degree sensor 23 and the engine speed sensor 25 can transmit information to the ECU, and the ECU can supply it to other control units, and no particular limitation is imposed.

[0013] Next, the fuel cut control will be described. A fuel cut control unit (hereinafter also referred to as an FC control unit) is provided in the ECU and is configured to stop fuel injection for the engine 1 when a prescribed set of conditions is satisfied in the state in which the ignition switch is turned on. Specifically, fuel injection is resumed when APO is less than or equal to a prescribed value indicating that the accelerator has been released and the vehicle speed VSP reaches the vehicle speed VSPfce to end the fuel cutoff, which corresponds to the prescribed engine speed at which the engine restart is possible only by restarting fuel injection for the engine 1. In addition to making a determination based on the vehicle speed VSP, this is the same as making a determination based on whether the engine speed Ne is actually less than or equal to the prescribed engine speed. In addition, after the start of the fuel cut, if the vehicle deceleration Gx exceeds the deceleration Gfce for the end of the fuel cut, indicating rapid deceleration, fuel injection is resumed to suppress the occurrence of excessive deceleration.

[0014] If the deceleration Gx exceeds Gfce, fuel injection is resumed, and the engine braking force is reduced before the vehicle speed reaches VSPfce, the ability to stop fuel injection is reduced, so there is a problem that the fuel economy cannot be sufficiently improved. In particular, if the air conditioner compressor 13 is in operation, the engine braking force tends to increase, thus, it is necessary to restart fuel injection at VSP much earlier than VSPfce, thus the possibility of stopping fuel injection is further reduced. Therefore, in the first embodiment, the control for maintaining G is executed in which the SSG 11 is instructed to perform a force rotation to reduce the braking force of the engine, and the deceleration Gx is controlled not to exceed Gfce. If the SOC of the battery 12 is insufficient and the SSG 11 cannot be instructed to perform a power rotation, or if the SSG 11 cannot be instructed to perform a power rotation due to other conditions. Fuel injection resumes when G exceeds Gfce, thereby inhibiting deceleration of Gx.

[0015] FIG. 3 is a flowchart showing a deceleration control process during fuel cutoff of the first embodiment. This sequence of operations is the process performed during fuel cut control.

At step S1, it is determined whether fuel cut control (hereinafter also referred to as FC) and deceleration are performed; if so, the process goes to step S2, otherwise the current control flow ends.

In step S2, it is determined whether the deceleration Gx is greater than or equal to the deceleration Gfce to end the fuel cut; if yes, the process goes to step S3, otherwise step S2 is repeated. Deceleration Gx represents acceleration in the negative direction with respect to the direction of travel of the vehicle, and is the value at which the acceleration in the negative direction increases when the absolute value of deceleration Gx increases.

In step S3, the control of maintaining G by the SSG 11 is executed (corresponding to the deceleration control unit). Specifically, the target deceleration is set to Gfce, and the force rotation torque of the SSG 11 is feedback controlled so that G is reduced to Gfce.

[0016] In step S4, it is determined whether another FC control end condition has been satisfied (eg, VSP <VSPfce, etc.); if satisfied, the process goes to step S5, otherwise the process returns to step S3 and the G hold control continues. Since the deceleration Gx is thus controlled so as not to exceed Gfce, the driver does not experience discomfort.

In step S5, an FC ending process is performed. In particular, the clutch 2 is disengaged and fuel injection is resumed.

[0017] Operations will now be described. FIG. 4 is a timing chart when the SSG generates a regenerative torque during deceleration during the fuel cut control of the first embodiment.

At time t1, if the Gx deceleration reaches Gfce during fuel cut control, SSG 11 is instructed to force rotation to reduce engine braking force, and Gx deceleration is controlled not to exceed Gfce. Therefore, the fuel injection accompanying the excess of Gfce by decelerating Gx is not resumed at this time. When the vehicle speed VSP falls below VSPfce at time t2, fuel injection resumes.

[0018] The shaded area a1 shown for G between times t1 and t2 in FIG. 4 is a deceleration region that is reduced by the force rotation of SSG 11. Since SSG 11 performs recuperation before reaching time t1, fuel efficiency can be improved by restoring kinetic energy of the vehicle and supplying said energy between times t1 and t2.

[0019] FIG. 5 is a timing chart when the SSG performs neither power rotation nor recuperation during deceleration during the fuel cut control of the first embodiment. The power conversion efficiency from the SSG 11 electric power to the torque that is used between the time t1 and t2 is better than the power conversion efficiency from the gasoline that is injected when fuel injection is resumed during this time at the torque; therefore, the power consumption of the entire vehicle can be improved.

[0020] As described above, the results listed below can be obtained with the first embodiment.

(1) An SSG 11 (motor) is provided that is configured to apply torque to the power transmission path between the engine 1 and the drive wheel 10, and the SSG 11 is driven to perform force rotation so that the vehicle deceleration Gx becomes less or equal to Gfce (prescribed value) when fuel injection for engine 1 is stopped during deceleration and VSP is greater than or equal to VSPfce (engine speed is greater than or equal to the prescribed engine speed).

Accordingly, it is possible to allow the fuel cut control to be performed while suppressing the Gx deceleration, thereby improving fuel efficiency.

[0021] (2) Fuel injection for engine 1 is resumed when vehicle deceleration Gx is greater than Gfce (prescribed value), while fuel injection for engine 1 is stopped.

Accordingly, it is possible to reduce the engine braking force and suppress the generation of excessive deceleration Gx, thereby making it possible to prevent discomfort for the driver.

[0022] Second embodiment

The second embodiment will be described next. Since the basic configuration is the same as in the first embodiment, only the difference will be described. FIG. 6 is a flowchart showing a deceleration control process during fuel cutoff of the second embodiment. This sequence of operations is the process performed during fuel cut control.

In step S1, it is determined whether the fuel cut control and deceleration are performed; if yes, the process goes to step S21, otherwise the current control flow ends.

[0023] In step S21, it is determined whether the deceleration Gx is greater than or equal to the prescribed deceleration Gfce1, which is less than the deceleration Gfce2 for ending the fuel cut; if so, the process goes to step S31, otherwise step S21 is repeated. The absolute value of Gfce1 is less than the absolute value of Gfce2.

In step S31, asymptotic G control is performed by the SSG 11 (corresponding to the deceleration control unit). Specifically, the target deceleration is set gradually from Gfce1 to a value approaching Gfce2, and the force rotation torque of the SSG 11 is feedback controlled so that the deceleration Gx gradually converges to Gfce2.

[0024] In step S4, it is determined whether another FC control end condition has been met (eg, VSP <VSPfce, etc.); if satisfied, the process goes to step S5, otherwise the process returns to step S31 and the asymptotic control of G continues. In this way, the Gx deceleration is controlled not to exceed Gfce2, so the driver does not experience discomfort.

In step S5, an FC ending process is performed. In particular, the clutch 2 is disengaged and fuel injection is resumed. The process of suppressing the fluctuation of the engine speed is then performed to suppress the change in the engine speed by the torque control SSG 11. Details will be described further below.

[0025] Next, the operation is described. FIG. 7 is a timing chart when the SSG generates a regenerative torque during deceleration during the fuel cut control of the second embodiment.

At time t1, if the Gx deceleration reaches Gfce1 during the fuel cut control, then the SSG 11 is driven to force rotation to reduce engine braking force, and the Gx deceleration is controlled not to exceed Gfce2. At this time, the deceleration of Gx is instructed to approach Gfce2. Therefore, since the force rotation by the SSG 11 starts before the time at which the force rotation of the SSG 11 starts in the first embodiment, it is possible to suppress the sudden change in the deceleration Gx. If the SSG 11 force rotation is not performed, then the deceleration Gx exceeds Gfce2, thus fuel injection will be resumed at time t2. In contrast, in the second embodiment, the deceleration Gx does not exceed Gfce2, so fuel injection is not resumed. When the vehicle speed VSP falls below VSPfce at time t3, fuel injection resumes.

[0026] The shaded area a2 shown for the Gx deceleration between times t1 and t2 in FIG. 7 is a deceleration region that is reduced by the force rotation of SSG 11. Since the SSG 11 performs recuperation before reaching the time t1, fuel efficiency can be improved by restoring the vehicle kinetic energy and supplying said energy between times t1 and t3.

[0027] FIG. 8 is a timing chart when the SSG performs neither power rotation nor recuperation during deceleration during the fuel cut control of the second embodiment. The power conversion efficiency from the SSG 11 electric power to the torque that is used between the times t1 and t3 is better than the power conversion efficiency from the gasoline that is injected when fuel injection is resumed between the times t2 and t3 to the torque; therefore, the power consumption of the entire vehicle can be improved.

[0028] FIG. 9 is a timing chart showing the process of suppressing the engine speed fluctuation in the FC ending process of the second embodiment.

When asymptotic control G starts at time t3 and VSP falls below VSPfce at time // t4 //, clutch 2 is disengaged first. Thus, it is possible to prevent the transmission of the torque fluctuation accompanying the engine restart to the drive wheels 10.

Further, even if the clutch 2 is disengaged at the time t4, the force rotation of the SSG 11 continues. That is, if the clutch 2 is disengaged in a state in which fuel injection is stopped, then the engine speed Ne tends to suddenly decrease. Therefore, the amount ΔNe1 for decreasing the engine speed from the moment when fuel injection is resumed until the time t5 at which the engine 1 starts autonomous rotation becomes large, which may cause discomfort to the driver. Accordingly, the engine speed reduction amount ΔNe1 can be suppressed by continuing the force rotation of the SSG 11 even after the clutch 2 is disengaged.

[0029] Further, if the operation of the SSG 11 is stopped immediately after the engine 1 starts autonomous rotation at the time t5, the amount of increase ΔNe2 of the engine rotation speed Ne due to complete combustion increases, which may cause discomfort to the driver. Therefore, after the complete combustion of the engine, the amount of increase ΔNe2 can be suppressed by the regeneration SSG 11.

[0030] In addition to the results of the first embodiment described above, the following results can be obtained with the second embodiment.

(3) A clutch 2 is provided between the engine 1 and the drive wheel 10, and when fuel injection for the engine 1 is resumed, fuel injection is resumed after the clutch 2 is disengaged, after which the power rotation of the SSG 11 is stopped. In other words, the clutch 2 is disengaged and fuel injection is resumed before the power rotation of the SSG 11 is stopped.

Accordingly, it is possible to prevent a significant decrease in the engine speed Ne after the clutch 2 is disengaged, and to prevent the driver from causing discomfort.

(4) When fuel injection is resumed for the engine 1, fuel injection is resumed after the clutch 2 is disengaged and after the engine has completely burned out, the regenerative torque is applied by the SSG 11.

Accordingly, it is possible to prevent a significant increase in the engine speed Ne after complete combustion of the engine, and to prevent discomfort for the driver.

[0031] Other embodiments

The present invention has been described above based on the embodiments, but a specific configuration may be a different configuration. In the first embodiment, an example has been shown in which a belt-type continuously variable transmission 3 is used as the transmission, but a different transmission type can be used. In addition, the clutch 2 of the first embodiment may be a starting clutch within the transmission. Additionally, in the first embodiment, an SSG 11 was used, which can transmit torque to the crankshaft of the engine 1, but the motor / generator can be placed in other places, for example, between the engine and the transmission, or between the transmission and the drive wheels, while it is on the path. transmission of power between the engine 1 and the driving wheels 10.

Claims (10)

1. A method for controlling a motor of a vehicle having a motor configured to apply torque to a power transmission path between the engine and a drive wheel, comprising the step of: driving the motor to force rotation so that the vehicle deceleration becomes less than or equal to a prescribed value when fuel injection for the engine is stopped during deceleration and the engine rotation speed is greater than or equal to the prescribed engine rotation speed. 2. A method for controlling a vehicle motor according to claim 1, wherein engine fuel injection is resumed when the vehicle decelerates more than a prescribed value while engine fuel injection is stopped. 3. A method for controlling a vehicle motor according to claim 1 or 2, while a clutch is provided between the engine and the drive wheels, and When fuel injection is resumed for the engine, fuel injection is resumed after the clutch is disengaged, after which the power rotation of the engine is stopped. 4. An engine and motor control device of a vehicle comprising a motor configured to apply torque to a power transmission path between the engine and a drive wheel, the vehicle engine and motor control device comprising: a fuel cut control unit that stops fuel injection of the engine when the engine speed is greater than or equal to the prescribed engine speed during deceleration; and a deceleration control unit that drives the motor to perform force rotation so that the vehicle deceleration becomes less than or equal to a prescribed value when fuel injection for the engine is stopped.

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